My 2 year old had similar issues when she moved into her big girl bed. It took about a week but we were consistant on this pattern: I tucked her in, put on a white noise machine to help block any noises from the rest of the house, SHUT THE DOOR, (she hated it too at first, but after a couple days was fine with it) then I'd wait by the door, as soon as I heard her get out of bed, I'd walk back in the room - make no eye contact, not say a word, just pick her up, lay her down and tuck her back in. Then repeat. It's a long process at first but eventually they realize it's not worth the fight. Within a week she was back to going right to bed, not getting out and sleeping for 2+ hours every afternoon. Good luck with this! It can be a battle of wills, but if you just give yourself some time and plug away at it... he'll be back to napping in his bed, with the lights off, door closed and sound asleep in no time!